Rotary switch with make-before break contact structure



' Dec. 21, 1965 w. T SORENSON 3,225,148

ROTARY SWITCH WITH MAKE-BEFORE BREAK CONTACT STRUCTURE Filed Oct. 11, 1963 2 Sheets-Sheet l INVENTOR %J4Er 2' [Yo/Pause ATTORNEY Dec. 21, 1965 w. T. SORENSON 3,

ROTARY SWITCH WITH MAKE-BEFORE BREAK CONTACT STRUCTURE Filed Oct. 11, 1965 2 Sheets-Sheet 2 ATTORNEY United States Patent 3,225,148 ROTARY SWITCH WITH MAKE-BEFORE BREAK CONTACT STRUCTURE Wesley T. Sorenson, West Hartford, Conn., assignor to Carling Electric, Inc., West Hartford, Conn., a corporation of Connecticut Filed Oct. 11, I963, Ser. No. 315,574 9 Claims. (Cl. 200-11) This invention relates to electric switches for controlling multiple circuits.

The switch herein is of the rotary type and includes novel captive ball contact means assembled with an electrically conductive armature for closing and opening the electrical circuits between a common power element and any one of a plurality of separate circuit elements. The components of the switch may be varied in dimension and location to arrange for make-before-break operation whereby a succeeding selected electric circuit is closed before a prior closed electric circuit is opened.

A further salient feature is the provision of plural bosses integrally formed on the common power element for indexing the switch in several circuit closing positions.

Another novel feature of the invention is the provision of a yieldably mounted rotatable armature cooperating with captive balls which perform the plural functions of indexing the actuator of the switch and of electrically bridging the armature between the common power element on the one hand and any one of a plurality of separate circuit elements on the other.

Still other objects and advantages of the invention will be apparent from the specification.

The features of novelty which are believed to be characteristic of the invention are set forth herein and will best be understood, both as to their fundamental principles and as to their particular embodiments, by reference to the specification and accompanying drawings, in which:

FIGURE 1 is a top plan view of the switch of the present invention;

FIG. 2 is a side elevation of the switch shown in FIG. 1;

FIG. 3 is a bottom view of the device shown in FIGS. 1 and 2;

FIG. 4 is an enlarged exploded perspective View of the various parts of the switch shown in FIGS. 1 and 2, some parts being omitted;

FIG. 5 is an enlarged vertical, central sectional view of the device shown in FIG. 2, some parts being broken away, some parts being shown in phantom outline, and some parts being omitted;

FIG. 6 is a view taken on line 66 of FIG. 5, some parts being omitted;

FIG. 7 is a view taken on line 77 of FIG. 5, some parts being omitted;

FIG. 8 is a view taken on line 88 of FIG. 5, some parts being omitted;

FIG. 9 is a view similar to that of FIG. 8, and further indicating schematically the closing of a first selected circuit of the switch;

FIG. 10 is similar to FIG. 9, showing schematically the closing of a second circuit of the switch; and

FIG. 11 is similar to FIGS. 9 and 10 and schematically shows the closing of the third circuit controlled by said switch.

Referring now to the drawings in detail, the switch of the present invention comprises a circular case, generally designated 21, made of sheet metal, plastic, or the like, having a top wall 22 and an integral circular side wall 23. Integrally formed at the lower edge of side wall 23 is a plurality of spaced apart lugs 24 (FIG. 3), which are bent to interengage a plurality of radially spaced apart recesses 26 in the edge of a circular terminal plate 27, the latter forming with case 21 an enclosure for the switching elements. Terminal plate 27 is made of a suitable insulating material such as impregnated fiberboard, nylon, Bakelite, or the like.

Formed in plate 27 are three slots 28, 29 and 31 through which extend respective electrically conductive sheet metal terminal lugs 32, 33 and 34 to which three different electrical circuits to be controlled by the switch are connected. Integrally formed with terminal lugs 32, 33 and 34 are respective contact elements 36, 37 and 38 which extend over the top surface of terminal plate 27 and which are arranged in an arcuate array. See FIGS. 4, 8 and 11.

Positioned on the top surface of terminal plate 27, diametrically opposite contact elements 36, 37 and 38, is an arcuate common contact and detent element 39 of sheet metal which has an integrallyformed terminal lug 41 that extends through slot 42 in said terminal plate. Terminal lug 41 is connected to a common power supply for energizing the circuits to which terminal lugs 32, 33 and 34 are connected.

Integrally formed in contact element 39 is a pair of spaced apart raised bulbous bosses 43 and 44 which divide said contact element into three arcuately arrayed detent lands whose function will be explained hereinafter. Contact elements 36, 37, 38 and 39 are secured to the top surface of plate 27 by suitable means such as adhesives, crimping or otherwise.

The top wall 22 of case 21 has a central aperture 46 to the edge of which is secured bushing 47 whose outer surface threadably accommodates a first nut 48 and a second nut 49, said nuts being adapted to mount said bushing upon a suitable mounting plate 51 shown in dotted outline in FIG. 5.

Rotatably supported in bushing 47 is a shaft 52 made of a suitable insulating material such as Bakelite,.nylon, or the like. The upper end portion of shaft 52 has a pair of substantially parallel peripheral flats 53 which mate by means of a pres-s fit with corresponding flats in a recess in switch handle 54 whereby the rotation of the latter causes the rotation of shaft 52.

Intermediate its ends shaft 52 has an integral collar 56 the upper edge of said collar abutting an annular shoulder 57 in the interior of bushing 47. The lower end of shaft 52 has a substantially square cross section which mates with the central square aperture 58 of an electrically conductive sheet metal switch armature 59 whereby the rotation of said shaft causes the rotation of said armature.

The top and bottom surfaces of armature 59 are bounded by top insulating plate 61 and bottom insulating plate 62 and secured thereto by suitable means such as crimping tabs, adhesives or the like. Plates 61 and 62, which may be made of fiberboard, Bakelite, nylon or the like, each have square apertures 63 and 64, respectively, which are axially aligned with aperture 58 in armature 59. The assembly of armature 59 and plates 61 and 62 is movable longitudinally upon the lower portion of shaft 52.

Bottom insulator plate 62 has a pair of spaced apart circular apertures 66 and 67 located degrees apart in respect of and aligned with the axial center of said plate. Said apertures 66 and 67 expose corresponding portions of armature 59 and freely and partially accommodate contact balls 68 and 69, respectively, whose function will be described hereinafter.

Mounted on fast on shaft 52 and spaced slightly apart from the bottom surface of top wall 22 of case 21 is a cam plate 71 which is rotatable by said shaft. Cam plate 71 has an arcuate recess bounded by a pair of spaced apart limiting edges 72 and 73. Top wall 22 of case 21 is punched to form two downwardly extending spaced apart stop lugs 74 and 76, respectively, said stop lugs being located in the area of the recess of cam plate 71. As can be seen from the illustration in FIGS. 4 and 6, the rotation of shaft 52 as well as of armature 59 is limited by the abutment of cam plate edge 72 against lug 76 in one direction, and in the other direction by the abutment of cam plate edge 73 against lug 74.

Bonded to the top surface of terminal plate 27 by suitable adhesives or the like is a protective indexing plate 77 made of suitable insulating material such as fiberboard, Bakelite, or the like. Plate 77 has two arcuate apertures 78 and 79, respectively, which are located over and expose the array of terminal contacts 36, 37 and 38 on the one hand, and indexing common contact element 39 on the other. Indexing plate 77 also has a pair of spaced apart circular apertures 81 and 82 disposed equidistantly as apertures 66 and 67, respectively, from the axial center of shaft 52. Plate 77 also has a plurality of radially spaced apart recesses 83 aligned with recesses 26 in plate 27 for engagement by lugs 24 securing said plates in proper position.

Apertures 78, 79, 81 and 82 also partially accommodate contact balls 68 and 69. Aperture 78 permits ball 69 to, establish electrical contact with contact elements 36, 37 and 38, while aperture 79 permits ball 68 to establish electrical contact with common indexing contact 39, both of said balls always being in closed circuit with each other through electrically conductive armature 59.

Balls 68 and 69, which are spaced 180 apart, are maintained in captive but arcuately movable positions within apertures 66 and 67, respectively, by means of coil spring 83 positioned around shaft 52 between cam plate 71 and insulating plate 61 whereby armature 59 is continuously and yieldably urged downwardly upon said balls.

When switch handle 54 is in the off-position, as shown in FIG. 5, contact balls 68 and 69 rest captive in apertures 81 and 82, respectively, of plate 77 and impinge upon insulating plate 27, whereby'said balls are in an open circuit condition. See FIG. 8.

When handle 54 is rotated clockwise, approximately 45 ball 68 is moved arcuately by the walls of aperture 66 in plate 62 to a first position 86 on common contact and indexing element 39. At the same time ball 69 is moved arcuately by the walls of aperture 67 of plate 62 to a position in contact with element 36. In this condition of the switch, as shown in FIG. 9, the first electrical circuit is closed between terminal lugs 32 and 41 by way of element 36, ball 69, armature 59, ball 68, and common element 39. Ball 68 is indexed in position on portion 86 of element 39 between boss 43 on said element and the edge of aperture 79 in indexing plate 77, thereby stabilizing the switch in the first circuit position.

A further 45 rotation of handle 54 causes ball 68 to ride yieldably over boss 43 onto second portion 87 on common circuit element 39 while ball 69 is moved from contact element 36 to contact element 37, thereby closing the circuit to which terminal lug 33 is connected and opening the circuit to which terminal lug 32 is connected. See FIG. 10. Ball 68 indexed between bosses 43 and 44 to stabilize the switch in the second circuit position.

A still further 45 turn of handle 54 causes ball 68 to ride yieldably over boss 44 onto third portion 88 on common circuit element 39 while ball 69 is moved from contact element 37 to contact element 38, thereby closing the circuit to which terminal lug 34 is connected and opening the circuit to which terminal lug 33 is connected. See FIG. 11. Ball 68 is indexed between boss 44 and the edge of aperture 79 in plate 77 thereby stabilizing the switch in the third circuit position.

The rotation of handle 54 is limited by the cam edges 72 and 73 spaced 180 apart on cam 71 butting against stop lug 76 and 7 respect ve y, Whose farthermo t e ge are spaced approximately 45 apart. Thus handle 54 is limited to a rotation of about which encompasses an open circuit position and three closed circuit positions.

Upon the counter-clockwise rotation of handle 54 from the third circuit position as shown in FIG. 11, the reverse consecutive switching action takes place until complete open circuit condition is reached as shown in FIG. 8. It is understood that any of the circuits one, two or three may be selected at will, but the choice of circuit two necessitates the prior interim closing of circuit one, while the selection of circuit three necessitates the prior successive interim closing of circuits one and 66tWo'7 In one important embodiment of the present invention, a make-before-break condition in switching from one adjacent circuit to another is effected by making spaced apart contact elements 36, 37 and 38 sufficiently large and close together and providing an adequate diameter for ball 69 whereby the latter, moving from one contact element to the next adjacent element, closes the succeeding circuit before opening the prior circuit. Thus ball 69 is large enough physically to bridge the gaps between contact elements 36 37 and between contact elements 37-38 whereby during the switching from one circuit to an adjacent circuit, there is a short interval of time when both of said circuits are in an energized condition.

While the foregoing description and drawings disclose a three-circuit switch, it is understood that, by enlarging the diameter of the case and by making suitable alterations in the sizes of the various components, the switch may be adapted for the operation of a greater number of circuits. In order to accomplish this, common element 39 would be enlarged and would incorporate a greater number of spaced apart bosses defining an increased number of indexed contact areas while, at the same time, a comparable increased number of contact elements, as exemplified by elements 36, B7 and 38, would be arrayed arcuately for impingement by contact ball 69.

A further modification of the present invention contemplates the substitution of yieldable spring blade elements for balls 68 and 69, said elements being electrically connected to armature 59 and each having yieldable contacting portions for making electrical connection with common element 39 on the one hand and contact elements 36, 37 and 38 on the other.

It is claimed:

1. A rotary switch comprising a case, a rotatable actuator mounted in said case, a base of insulating material on said case, an electrically conductive armature mounted on said actuator and rotated thereby, means on said actuator yieldably urging said armature toward said base, a first electrically conductive ball and a second electrically conductive ball maintained captive between said armature and said base, said balls being spaced apart relative to the axis of rotation of said armature and being in electrical connection therewith, means on said armature to move said balls in respective arcuate paths, an arcuate common contact element on said base, said first ball cooperating with said common contactelernent, a plurality of separate circuit elements in arcuate array on said base, said second ball cooperating with said separate circuit elements in succession, plural means on said common contact element operative upon said first ballto cause said second ball to be indexed upon any selected one of said circuit elements,

2. A switch according to claim 1 and further comprising means on said actuator and on said case cooperating to limit the rotation of said actuator.

'3. A rotary switch comprising a case, a rotatable actuator mounted in said case, a base of insulating material on said case, an electrically conductive armature looselymounted on said actuator and rotatable thereby, an insulating protective plate on the top surface of said arma ture, an insulating protective plate on the bottom surface 9f said armature: l O apertures in said bottom insulating plate, said apertures being spaced 180 apart in respect of the axis of rotation of said armature, a first electrically conductive ball nested in one of said apertures, a second electrically conductive ball nested in the other aperture, said balls being in electrical connection with said armature, a spring on said actuator impinging on said top insulating plate and normally urging said armature toward said base to maintain said balls captive therebetween, said balls being movable in respective arcuate paths when said armature is rotated, an arcuate common circuit element on said base, a plurality of separate circuit contact elements arrayed in an arcuate path on said base, and a plurality of spaced apart bosses integrally formed on said common circuit element, said bosses dividing said common element into a plurality of separate contact areas, said first ball making electrical connection with said common contact element, said second ball making successive contacts with said separate circuit elements when said armature is rotated, said bosses cooperating with said first ball to partially resist rotation of said armature and to index said second ball upon a selected separate circuit contact element.

4. A switch according to claim 3 wherein the dimensions and locations of said respective separate circuit elements and the dimension of said second ball is determined to cause said second ball to close the electrical circuit of a selected separate circuit element before the circuit of a previously contacted separate circuit element is opened.

5. A switch according to claim 3 wherein the arcuate length of said common circuit element is such that said first ball is always in contact therewith while said second ball is in contact with any one of said separate circuit elements and when passing from one separate circuit element to a succeeding separate circuit element.

6. A switch according to claim 1 and further comprising recessed means on said base for receiving both of said balls to index said armature in an open circuit position, said balls rising out of said recess by the yielding action of said armature.

7. A switch according to claim 1 and further comprising a plurality of spaced apart bosses on said common contact element, said bosses dividing said common contact element into a plurality of contacting areas equivalent in number to said separate circuit elements, said first ball being indexed by said bosses in selected circuit closing positions.

8. Aswitch according to claim 1 and further comprising an indexing plate on said base, both of said balls being movable upon said insulating plate by the rotation of said armature, first and second apertures in said plate accommodating said first and second balls, respectively, to index said armature in an open circuit position, a third aperture in said plate exposing said common contact element, the edges of said third aperture assisting in indexing said first ball on the contact areas at both ends of said common contact element, and a fourth aperture in said plate exposing all of said separate circuit elements, said balls yieldably rising out of all said recesses during the rotation of said armature.

9. A rotary switch comprising a case, a rotatable actuator mounted in said case, a base of insulating material on said case, a common power element on said base, a plurality of separate spaced apart circuit elements on said base, an electrically conductive armature mounted on and rotated by said actuator, first and second yieldable means electrically connected to said armature, said first means cooperating with said common power element, said second means cooperating with each of said separate circuit elements, said first means always being in contact with said common power element when said second means is in contact with any one of said separate circuit elements, the location and dimensions of said separate circuit elements and the dimension and shape of said second means being determined that, on moving from a prior to a succeeding separate circuit element, said second means closes the electrical circuit of said succeeding element before it opens the electrical circuit of said prior element.

References Cited by the Examiner UNITED STATES PATENTS 1,624,374 4/ 1927 Swoboda 200-11 1,885,865 1/1932 Schneider 20011 2,033,252 3/1936 Parker 200-11 2,432,067 12/ 1947 Morse 200-11 2,805,291 9/1957 Eickhorst et a1 200-166 2,817,722 12/1957 Johnson 20011 3,121,143 2/1964 Landry et a1. 20011 KATHLEEN H. CLAFFY, Primary Examiner. 

1. A ROTARY SWITCH COMPRISING A CASE, A ROTATABLE ACTUATOR MOUNTED IN SAID CASE, A BASE OF INSULATING MATERIAL ON SAID CASE, AN ELECTRICALLY CONDUCTIVE ARMATURE MOUNTED ON SAID ACTUATOR AND ROTATED THEREBY, MEANS ON SAID ACTUATOR YIELDABLY URGING SAID ARMATURE TOWARD SAID BASE, A FIRST ELECTRICALLY CONDUCTIVE BALL AND A SECOND ELECTRICALLY CONDUCTIVE BALL MAINTAINED CAPTIVE BETWEEN SAID ARMATURE AND SAID BASE, SAID BALLS BEING SPACED APART RELATIVE TO THE AXIS OF ROTATION OF SAID ARMATURE AND BEING IN ELECTRICAL CONNECTION THEREWITH, MEANS ON SAID ARMATURE TO MOVE SAID BALLS IN RESPECTIVE ARCUATE PATHS, AN ARCUATE COMMON CONTACT ELEMENT ON SAID BASE, SAID FIRST BALL COOPERATING WITH SAID COMMON CONTACT ELEMENT, A PLURALITY OF SEPARATE CIRCUIT ELEMENTS IN ARCUATE ARRAY ON SAID BASE, SAID SECOND BALL COOPERATING WITH SAID SEPARATE CIRCUIT ELEMENTS IN SUCCESSION, PLURAL MEANS ON SAID COMMON CONTACT ELEMENT OPEATIVE UPON SAID FIRST BALL TO CAUSE SAID SECOND BALL TO BE INDEXED UPON ANY SELECTED ONE OF SAID CIRCUIT ELEMENTS. 